SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '486c3553669ce5e2fa29605c02a54695c7d8974596ad1c3db718204f4ecdf310' 
  AND token = 'LrIQXr3XIII838N0jEqfcy74NxJedO9xMJvcakrPCSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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