SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '274a619d6a9fdba62f062adc170c07630da71289dba00b57ca7976b5ffbf881d' 
  AND token = 'oFRyKW0g6neg0Azx5HvtplxktDfXn46ZG1tkxF75K1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}