SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '077f907d862656a65116800ebe39d136dd553b868e494d4bd9ac201e97d9253a' 
  AND token = '52GVpFKozRPdrOzIYtegz54HWtoDfgoO3K8uAZN3zsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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