SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a335a055d3a969092e4ce00babc828960b859cfa1e3c3e97ed5a2192becd834a' 
  AND token = 'XaVj0W57luUvE1PWByegV7haftjIB9CdpvDd5Tv/bDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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