SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4574d40ed2ef651f4a4041b6baf05fd132b893883a1c465aeca9f2e448d191b3' 
  AND token = 'sxPotCb87+TiKimXbGAWANvF3UGRnvwxoB3DLvB+KpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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