SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cecb68a4b26929fee4cb8a754a69973bc46e4705d42637afee6c807281573e2f' 
  AND token = 'S+JbFEr18kmOzi+HARXrR5q+xbvPyDyeu8Q4iL88zn4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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