SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5150f673127b4e729deafe8a9324d13a376d17a0f8025adaf9c722ec09fef32' 
  AND token = 'Yy6gB3fwd+/fiBxsAkq95fkSEccvykHQgrBk9huoiZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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