SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '676b6a9f745709cf3d423fa40284f0bdf5870446f052ce20a084b650d456c6b9' 
  AND token = 'XW7626BgtvpWfKEDzzluZVUo/9ov45LWEGJaY0dblrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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