SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f584b3fa6fb7c1b5b90a8653f5923354bcd30e2466d12d7c2aa185d11c8fd63' 
  AND token = 'au/Lv9qDc5jnA128oitBhKbuTLeOj2VW9CJnShCBKbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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