SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8150c25d37bb7df423b15150aeb6f780968727e658f7ecbdb44c317f03e0ed4' 
  AND token = 'c5WeQDT/85Rgz1DCVlb9hYPcVUJCAbJ3PLy8f7DeQk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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