SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46cbe991b2ad549135d024ed566093ed4d9b89a387d7a91e9fced56fc2c9837b' 
  AND token = '0to4zJ+il0k8UokXs7yNH5Z95VHQAo+SaFq1Qt8e+tA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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