SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afef4446d9a07ccb14b2396df12ca5181f8cb6a75535e2133e9bd4cf48ee19cd' 
  AND token = 'ai9SSSm6QpVtSWmOzNGVb0dKDaMeMF+ANt6NzMhSpds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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