SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9511f1df8351ff14d5e240edbf52cd46068699ef711f8c86a4cd13dc6610baad' 
  AND token = 'n/sbgY7IUBUt7tSEPthaksyquusSKiKnhHu/rUcoNwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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