SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24c4ac514aaa213b8bfe031ee757c898fc61822342b14daf3e5a16c5c9cbfe17' 
  AND token = 'UfXVGOGZ+bVaDwi43+VF3zN0Nj87vYHLrCLYAvNN4NA=' 
  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"
    }
  }
}