Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c21843c28354aa09d07463a7867c737432b66edd1807ed969a5cedad11a220a3' 
  AND token = 'PS663ctVqRKSi0ahBApMJNmxjI0OEuh7YOQGpKIfQvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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