SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4b3cf402fbf126fcbfbafdb06af57cd65adbb1a1ca42fd46e7a1b5c42371d79' 
  AND token = 'cE1xi5GUdcQtISP0EhJb9jb7Cup9S6jyEELMMoRUn+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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