SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab1f4b618c4716cec4f7180b46fc51b62aed29958143d924cce1940ed4d03bd2' 
  AND token = 'ybmriC8U6MK+JSrw5QfiZDrrVtgI4Pc0JC9uVd73Nb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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