SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c68160ff4cec13996b472ce4b1db8b8cc281673ce4235a0dbbdc8585df97fcc' 
  AND token = 'UHUYhbuhmxG8DMyIzQ1bAB39TD+CSbJ82MhSCJ5hfio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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