SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23f7824723111ef7ea79b4870c915bc6dbaa64f835702398c9598fbbfe91b7c8' 
  AND token = 'o7JKkPsoMA/mjLQc6CEDoaWFFcA7htxyi2ucIbmxyWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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