SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67c38c70cfceb3614f1f3d081d04199cef6365efa733d2a9b4cea774c8f3ebe9' 
  AND token = '2KRZtLYvDi27FIuzy24H3otU7rQgTxUhg+MmcQu5Wto=' 
  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"
    }
  }
}