SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba28ba62ecc3e6d1650690bac4e9ab146c63d9a4731736f1bd5273cc35718555' 
  AND token = 'z4SYOCRsglou3RvyERitdMZZrZuE8caKlmpJDF71ikM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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