SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '938e40a7a55e3a190b130516969bd79abcfc66d73221116964c39d1b895c303b' 
  AND token = 'IASejp26yrLhLmXL234g7wvEwrmUTNd5VoAYOi8B8Rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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