SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9e99e7586b7114d688dcb987cd2b02d524e85d4f81d9824f8ccb29ca5b2217f' 
  AND token = 'vtmQRa5lEb6dHVkyUOcaJoEQ/ayV7DOnshm2NEUt3wY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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