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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f3ee08e1d627073cd85f5ea11c2bae1abe42016e80de0e267c8c3e6a1135d00' 
  AND token = 'BSx23aKUtIHN3wvjqFv6z/g/BJ80aNjPrguhI60hQGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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