SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e11879929c3cafea72aa20844cc9aa6504234d89c2231a2d8d7d63a36f22a56' 
  AND token = 'AIxN40PV0hmTVGFVK8Cr7wXCAlxVILG7JnBF+uqJDCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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