SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '775359e72580e259e3544ea041958eb1555b9bbecdf2e393f46942085944094f' 
  AND token = 'wg9lCFPhgGQDtMw3qoOAYyN9J5xvq2QXGqvO+CvQ4do=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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