SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f6289d8ead668af15f1a15362c57266f606e7f9bcc06fe1826bbd7c0593c7cb' 
  AND token = 'eezwsd71PU/3uv0pZoZNQgwoFUDplRMCVnalW0EbHQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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