SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03197ea8024ed7d707dc2431958b91421729242bea08e85ae7e7c547dd36ac4a' 
  AND token = 'xD4AeFbCTMdqp4ucPW4fWDphBBUE5nuGbgEjQeeagHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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