SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '241bf0dadc5212b7716a98fef13d93615363fcf75908ae251060274e29213c94' 
  AND token = 'scVypnxbL7IejFP2+F6hUTMAEmTG7pI4XE1WirAhWXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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