SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf63eb828d786b3febca39d9ea90ca3afff754d2d0df4449af15633e948f0527' 
  AND token = 'F9ZAcMpE8GjSS0JpAr2GDTUM5cmOlcLXkX9cKBeOVsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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