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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd39b62a49bfe85fa7a26d39e3c0f695571dc75e1d56416fe2f9e8c8fa7d9e0e4' 
  AND token = 'Akg/VH8Lt92AKoX/AnYwqXX9Qlj4FXRKFzTsFasMMmA=' 
  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"
    }
  }
}