SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a192637cb97fb125f1b83ef2225dad00f95db5d86d40b1f14cdf97543b1e3cd' 
  AND token = 'm3kym5rhJQC9A7dPmM2lMsHcyPRdIj6jmqmdi/nt3kQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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