SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7a80492ff1fb98a205d3654ee4336f51d9cb6d5406c0e0cae7a411f93505ec8' 
  AND token = 'R5QYff1WmJaKkWp6TD7QpujjUObqxfeTMisFY16UBow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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