SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff5da0fadb649b2bb22f17b744acf5d6502a981ca5142aa9e6af9181f37ffbd2' 
  AND token = 'ZZjUs6gjG6h3IJsCMdBSFaBGwG8QYiy3XUyNyhuYmVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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