SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '869a2009eefc5e12553318e1d1a87266945077c2feea78536cc7fe24655b257e' 
  AND token = '1ASQzn8Sv0fxT+NAOpdiiBl+5K/UZU6ub+xVSmdwvmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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