SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a39d0858d27b908729dd33effbc05156eca9f6ea8c07437a930a55ecbe404a2' 
  AND token = 'AYmZ9WfqtwmnbhqkWbhWkRoiUQFPkVMq0Do1TGFM3zU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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