SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '336518b89359898ff03e7e437689ed921bde04c92d1831a3fed541f425a6cd72' 
  AND token = 'L0D2lmYzeTWSYoLOAzPml+ICOOWSSBTEerraQ1jpPqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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