SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77aa315bd347a631c092bf9d373fd12d0cf5faeebdb154744e09c892788d2dbb' 
  AND token = 'QyLjMfA+JP+4f/6u0nwgkMD5OLYAEcYLrfQ8iQ1NcHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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