SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4c79a7c001b0c14f1852e12a580f4f4098204cc38733685b2c6d938a80dfe4c' 
  AND token = 'NcKjsyiFOgvLGO04Y57THmZQne8hm+YGwmjwGkDKOYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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