SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ffb67fb2867a297cee9088652ec60772317a7dc398452c778fe553c24a20ccd' 
  AND token = 'eLGvXG+l1lTDYClu9Xe/uVyTYsPNRVWw/u0+IXnffqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}