SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3aa4b7f8f35d9f304969c7fefb33c0beceb209390aec7dfb8ca8f51565f9b2ed' 
  AND token = 'AOCUxzlHDWms9m8qLZkGl1Slp2vcRcsTHy5z0bUVREU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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