SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38e39fe3b000a9fae8d6b5128513ebcb6cba21013b2861873adc16996d5b2e9a' 
  AND token = 'QfNcNtqtwWEvAZJ6otTUaRcSllA7zFawTFfc7yKRtAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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