SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '186c74b145402a9fc29303b1075629459d84dad58d03809d48fca6726d019e1e' 
  AND token = 'B9Yuzk82RntXmYnnvG4LoljpqD2jkAHHEzqdHmdzp6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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