SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ae7f975a80ba14db8639e8b25845421be358587319bab3fa84b46511a4732dc' 
  AND token = 'hgGDvSO4ouz+BNGohaMqV/SrueLsJoBJUuKE+i/E25A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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