SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55e11dfc9366057fa2326fe3435645f73b01e6b23b7abd3d4dd13c4720cd5c7f' 
  AND token = 'F9RFiGT8RdrHfCSlKs1Ucl472JhV2Tqc208hAmNYRnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}