SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00d70ba89952abda987f2ce3fcb2f6e6afa281ec617bb615544e4e55d7879f7f' 
  AND token = 'FXY4rLjPL8aR+FHh9i+wtdYkKMbkV/1Py/ZVXvYUtUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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