SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98748ce87e40cd8b495f4a1886470ded53e66dfa80aaa67d4411da10ad2af049' 
  AND token = 'ISaQZebIPTtuNLoegCSyXYoB/Jy+j/Pyp7dgZi5cmA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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