SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53af745ef26fb45276f81e962993d68942b97e9450d35cdcda7520c114fccb17' 
  AND token = 'bvcoOy6PjvZ0IuvlqA7XLZcrCCHBK6IazxhPnONNpP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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