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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6517bd99637e45e70284ea7ab16f6ef85a4eb8b63efd7a536be0ef057320e1f' 
  AND token = 'oYJ1T6JidF5kWR2BQ2Nggt5Iry7HR1bcV6Y3EKSAfzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}