SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39325676a316c83dae0ce2495d50720287cfa86f7ff29e5fae460d6c40d83331' 
  AND token = 'nTTBYTuRmwH5YDhnkhSbzJAZLjd8D7yy+p8XccBRoYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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