SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '187c263d50706633c261a30e031083b202f77dc709a975f781d6c3524576433f' 
  AND token = 'jBDZ/eONDfS066SUwjZ9uDfAgj5x4klrUPOJNG0gVq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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