SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dade31b24a486ac7f8e42a1e0d678502e9d89f68ec9801da68ca55ce16782f84' 
  AND token = 'Dv/I2YjB6Gvsg8deySUvPNNejuxoRUJfQIqNAZiVo3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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