SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '281bd0443554f69e3973677d06920d5d4f8c9ed943a5a425f44cf8a88f56b686' 
  AND token = '1UGULIPKOCLQUQA4jehsVf25ja1PLQ1hr/nglComdpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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