SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa84c9739a71b3e31727bb89e4373b10550419fce057c9bb2cacbfcfedf53749' 
  AND token = 'ZmRjqvDpdzjNYa3hlfg35oOlbHX9S5KCFlbxyWG8Tew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00072

JSON explain

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