SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc8ed429befe65b686f59951f14100ee4c617eca94c7f773f120778b4aadbb3e' 
  AND token = 'PrTINTnPF75gefgQIe2UnLFD9k2FvbVvQGa+fTpqYiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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