SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a18f479daa54e2b899085b545dd81a305b7db2d9466388c0e07bc8302ed0d9f' 
  AND token = 'ViP1bz5jTxWJe/TsG+eWYUg1pluePLSna20bHeSDS5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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