SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '139ba9fc841afee32b992dcdb126cf7ff6c06896f9c5a921eebe6a9909aa2dde' 
  AND token = 'PY76rKcGoS/MzpagNpCj2W4hGmVgW7lsKFjzJaJCy1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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