SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51c916aa7965341cd6612a890bbfb50648ff27b4fef0844759f20d135a1b9910' 
  AND token = 'BLfyWSGo1myt29BIpF/g8fcMaGGCHJVMsAdzanHTi5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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