SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b2e84ab41ac6e2e0a4bb8dcef119cfce3ce77988b9fd9134375400e1a0ddd03' 
  AND token = 'Fyf2/1NTZFzaKb0yz2BcPEtaWA2UBxg8kWH5DcJox8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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