SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f41779716561264ccf33c274a66a28b145772bdeda755f4f78e0c86b308a1199' 
  AND token = '2UUt61DDYBDKSuDfHXgYgBt2HOWGRuvzobEnTnK2Nps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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