SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f9d38b10b5544914d1ab44cef28dc7d79a67ac1a76694600141e3bbbb9831ff' 
  AND token = 'RWqXku9GgCsZEaD+BF6ZAM1YmSivQLjXT3526IlaWig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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