SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78e4ac7d01656c22213d1ea01ee432faead30cbff5d168dcc5796456218e39db' 
  AND token = 'NPOTh9AJzYu5rpy8zSg3e2dRWrWVWnImib3stCU5ZuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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