SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '270112c89191141839116b7a9c56dc121e241603cbd295816994902e686b0de4' 
  AND token = 'Vrk0wuZJj18WYM0WBcdOJyqC4Yads0t1yO/NAuPX5BM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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