SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3c9e6218d9142fb53c79eea5dcbe943aac6adbfd2727e747fb84ff0909e7a127' 
  AND token = '6Bznd8+4Sso0wLzCBM/SSaQjVIwfT1EYehnOsW3xgfs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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