SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a16244b9e02182e39608bee6666b273eb7151d0b109aca21c13748caac3cee9' 
  AND token = 'd6m7YoQmmzoHJ4gb8Bg87F+mm7BbnGhMi9OIjZZX9o8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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