SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7562936c5dbfa39c7977e54ffc3edeb4af61d6dd1050430c20cda23f319f843' 
  AND token = 'oSXq9azsnqzBsoadud7I+EjXlLc+qjE1PwdCechKpcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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