SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e92158f56d7e4ebf87bf3e2cf6157f26743cb752923468dffa22d22a9147d684' 
  AND token = 'tbUVs96R4UfAt6impZbIfo2+jy1NcO+RN8d/W3zU9bQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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