SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd530b83a792fc883f5d40b065b2321494bb2816e80203a9494fd39bf19d8f3f3' 
  AND token = 'Vgn2DXfv+ozz5k8hz1BvGbDioDib9fKBvMiwKYXcXCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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