SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f19ccfeff808b46291dd88068b23d4600d040e66855121ce2361f5b23eb8b8d' 
  AND token = 'CKOuN7rolRE5JPzn2qB/pLs/kf7nWYOy9OzgGjxL9YM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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