SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82c2d44e20a43d6dcab075616c489b062b3350ea8c53722457bc3a9f1312c10c' 
  AND token = 'ksSg/SGCquhx41FSnQlEnIl9YKPrQxwDQXBDEy1vfM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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