SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8b6cdc7a6ee9dfc0fe89afee1904c9e65eac0426a19488f963fec9022192ee7' 
  AND token = 'fRucMR0BmH5SnuXwgS3d8VYWRv0WLGwgbYj3Iuf1xs8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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