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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30e2eba00d98e1a9bf1236d8a8a421690209661d802d7f3bbb006497808f7e83' 
  AND token = 'H6eUvQv3rsLj4Uqf9f4olkmvEXtSARRencZQRBeY5C0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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