SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83837c5afd7cb71098cfab0205d996e5e8492ddcae8dca7b4b4ad9ccb725cff4' 
  AND token = 'hTBDHSwXagqKH4fth181AzG/tvpgZuLUvUe7CltNsbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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