SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e21fde0b6c1ba8425beed281d954edcebe6495e103d8fea3800d1235c6b09d1' 
  AND token = 'obA/sA7EQUKElxOuDoOeaTjUMH+bdHkTZ4skZD4fzfs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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