SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7120489176dc766fa583f968d195d5a304b4fc1004a46edb45797c4099dcb8d7' 
  AND token = 'ObN1/qosRykaJS4EOWSl8VMlVCLUejoGwfKRAGjMAoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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