SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cacb4df70f44667a5f03d77b5253d050b7423e0714d0b88d0c228ffc0419dd3' 
  AND token = 'coBExYXqXttCnD4u1FNMoyY9lwgF4qXIa03da5ftszY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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