SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd57dd6a84ebb360a4910992838de6867be05c310fc46b0f515d43e2a3bf65aef' 
  AND token = 'e7CbUZjDC4eYkoGNHe8pkATP2q7IMqTVxNhyL8qfN5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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