SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b8ad6e4fa308ec87e7ec7c9bcce324fafd85ec38b2ef291398442b12787661d' 
  AND token = '6O7Jpu2CB0iDJw91F/sgvW6le+ZgQlSTWwBXCXo/KJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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