SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6047694ad57bc8b822900c26a8c6307e98822559936f57e9466121deb4bf30ce' 
  AND token = '/REggPGifTznKvmagJT+bsvnVEv/WnYFfL/CRdYrRdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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