SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14df650fb905ec2685e1e9f1fd46f49161f43fdd8ce761c4cd908733f73a2d88' 
  AND token = 'cJ84GRVIorjhh0ywbe4LjDFVx1+37GWt7RZmYYhTwzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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