SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15fca540e8d379e265a1915b3686eb6acde800d16200ebb5cfb6e2fb41c81434' 
  AND token = 'JryO+MB6EJ9SJyAzwwCezH3UcDXbXhZE6SHYt5gvTEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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