SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06801d272de937091f8af47b1a10528e78184d69ff10f50bc93de1540348c062' 
  AND token = 'KcxCboKW9IG0WdnYfxzwyebHgvdy4biHUZpzOYZ4iaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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