SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c941bd940f2109127a30a3657cca90eec5c8a7fcccdcf6e972b5b597addd5a9d' 
  AND token = '6U4d1B5D5gjWvSmIevPUt0qneOCQtI3ovghM4udsUcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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