SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3236cebef9dcd368adb09fcd187d3010217c40984d34da7d658a2b4441962950' 
  AND token = 'PlV+BbObfHqNs0ErACHlfjTqM9oQik4m2onYTFdOPOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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