SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '296a972f356e072f846bfaea757788dc13feabf79ace5b6ecbb615487908dff6' 
  AND token = 'nvdEd9MPWM6BDlWzVkMmnIbBUp/pBiKiIP2W1I9DLIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}