SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c476ad74a6be21ca6979e8750f26b08a15a6f4f037dea5bd31a9ac7900b2babb' 
  AND token = 'ufJ+Di/7VwG6qUzridoPVeOK1LF/PNYvpHIrFjUaLsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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