SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d63f872d8b7f0e0fec3f5d718508bf6657574c7bcaa562f878d04641a23dc15' 
  AND token = '1r5KLXKoQVwkIDC6AwKz/YfRxr8hjEhdPQqkF/M7bwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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