SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09ed3faa5256041cb56487ba09eea6805ae24467f8f564df7cfe52b48306b496' 
  AND token = 'qkJRWOjhBq49lWx7HV2wANkyuUDe+sYKGonO9TMibqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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