SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11940056f6aee7c8247655a616ada8d1e79e673d0c62fed78811546d39bf955e' 
  AND token = 'v4gnKbUMefSFKj1MuGN4yC0RWyM7w03UV0YwwncJ8is=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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