SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd48946546de81b8abd51a91240d5ff2af82cb435fd365ad8bc43c125c75e2267' 
  AND token = 'ITgpjsDNrtSrUxVSwhihCgHEHa245JFdEoKK2/s18Ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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