SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b912b6162768b98dbef2af4f80b29c08e7bc0b5e0163d6d4204dd260ae92a975' 
  AND token = 'T2WzriTd/0k7bn21rF/e9NZqhYVbfLiyTzxoFpRiz6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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