SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7286908ac8e10f41b812b00c69a8581c190cf08d9549b358735c849f59be30d' 
  AND token = 'sGAYt25nDUbj4HxjB5aVJkfE54rUTsj5ELOkSMEhLb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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