SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffaac5478675686575b8264a4eab1ff31ae78ac1ed2280608b043bb2ee534312' 
  AND token = 'lVXxuw8NhcJnkx10Dz/Aitk6LqlxeQnzxRhVOydA4/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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