SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03d1433680f8b05b7d9eaa85618911df2c12c9f01012f780a1741dbffba321a6' 
  AND token = 'k2iQXdZMvIBhDvyS0kZ5xKQgkRzri45E99gu+PVVEYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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