SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c3d89987cfc31e9d25e2af96b1d7d01315b8472ac92b9b741437432276f548b' 
  AND token = '42KPIRFxHzJWrZ4/4DPjfqrrMw5+QRrsi6/tfhTWVis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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