SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9deeabf9bf3cfe209cff5055008cbdcafa9c3e852e11483005cd3672ffa3c74c' 
  AND token = '6bEy+8tWMcBKfmpWTWn5B6jpYq/WI7FsMgwICGtqEQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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