SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d508e52bf9d34950bb27da3fc00bfe595b66a5622319928bd0a53ebbd37ef5b' 
  AND token = 'dTB9DRXCOuWKnCLlMU34pcs/u0+VcUiZyte8VJMXq5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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