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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a51e328478ad56f3015bc754d4b5164815a5e04084c2d39ce1d697d4d78e9c7' 
  AND token = 'BTXZhwvjP8F2YMdUaxquwKwqQb58OUnfpQIWItfRd4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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