SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e16acb4464364c6fd163267a2cd34cca1cfb980ec19bcf40e79d1bd5f2e0bcde' 
  AND token = 'lxBNMEcROHeRn4OgsmHqq7sEpJJOHhmMFZtJ9pfKkqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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