SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d805713012afdb2cf80287bc018447fac53a7a369b9b844ceed8362162bf11f' 
  AND token = 'FmsobsYnBpGNdNFFXgGDt3PWTrdtPlSli+v+IuSJ/H8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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