SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9361ff677980dc2ea32a764a4792b03d600558b287ac724d559e0767a82dca8f' 
  AND token = '++NaZSC/gDiQqjzByD3jhf73ZCqlZX/1W1AYCKwap+8=' 
  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"
    }
  }
}