SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '384f51b44257c54e9610e9a96ee67f7c18d3a869bdb40f3e84cde02a41303f4e' 
  AND token = 'OC6hl4AQmmFqYIhrUi3bl+XV/cQbBvjrnXEfgA8N/wc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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