SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a1c80874089e0e6b7c1d8477d783041eada43a31ab5ec428664e77155b03819' 
  AND token = 'DOPoPVucGfNlPcpAKRSJVRGBM9iA+pH1ssmIpZrHedU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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