SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74e952e9c595734bd836e7f04937242a54f8ce34af028a118f45375cd1373db4' 
  AND token = 'qXCIpd+ewlEGiVfr0mHkmgUvJWqtTwO0ZyhnJQNLwek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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