SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6283790d21e4292ac80133e5d7b90ab9d52d81fe64a43cf74ae1ff9a55a9813f' 
  AND token = 'dbJjdo/AYfKoPchsmhHDJFEk27HvWoCnuM8jzfv8U+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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