SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f3aa40923c9383f59b9480c1d78d98ef8c9e356942be2a46ba595d677b6ad40' 
  AND token = '3MTy6Tl5Fdhu4BIJnYjh9tqAx9Gi2X7V4LOo/FCvxu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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