SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc1ddaa811b6a873eab01b973e84587a2489125f716b67e0f1bc1d7f553b7704' 
  AND token = 'yiUpri2Lj7Gw7d5dqwHzEKrFa/6vnGP1oW/l+Q+wxB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}