SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dc96345ce53852cde110f6a0dea45c4dffe303942264e3939260137487e0fa2' 
  AND token = 'ki8R2V88MExkApq5PugpWt+mGiX4D2AbRV4FjtQitTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}