SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd03f8298846ba61337bf6e7f1822395425c42b0bf7a57ac58d237dae4d15367' 
  AND token = 'QpcwFqbXDsBE9kaTiT1GbTouELBA2DZaW6dWTcY6vSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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