SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6fabedca514e23ea0df321b2c362870d530110ebadf6a74ae135f918d45f35c' 
  AND token = '1wUHyhLwE88k+MlMLZ58aRxfOSBvSV3JEFAqsPwH9rU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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