SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26298548c06e12469c0ca8531aae0a9252907944f55064c23090fe304750ed14' 
  AND token = 'aTSgEHBDBGPowPqDN1aVIFl8I/cZGK+Jhu1ErOjjy9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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