SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f1f2f72b88a4fa94cc2da53e8ce99d99c91e1dfd7b23e3e7addf9b830390236' 
  AND token = 'gEsJtqyNVKF+OOL3wXDgVjjmWZRhoqLdi3GJs0oQojE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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