SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1274d3d7e09a13f3e7450c30e9442d896df400de2c5c4d0b351db71a8cd0a3ab' 
  AND token = 'NfoEPv5z6tFDf/+kb38Y4LAM/q6N7F0UZFT7APUgXDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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