SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9f93c515e6a89ec6f21397345141d78f6d04a200a4a7c1c2295685d43f2a77a' 
  AND token = 'YZDxI3lzPrwJMOY0+oB9+FUeraBjzLyFdJqQ8mmo5W8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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