SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46a48708b29390bfa74b9ed2df09fb58ca5d1be8db458310a36c2007c16d6737' 
  AND token = 'AqD4Z5RAwHPr7jYWw3NjteCSU7ag7VceMLPv17UNxrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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