SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '183983deaea56409fda6d7116a356deca59a319c21e3f84f610c56107978fc62' 
  AND token = '9uzLJBfAf4lrbgink1wEdt99YOHfs/2BCkHTd0hbZg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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