SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9ca900f05645bb157c0ae431a823795f16b312950f51c1190e81906f639b6a6' 
  AND token = 'YcMTIToSgVEJpCdkpc3mJVC/ea17bnGSWUdnbjED2Yo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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