SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'baf43ed2795b4e01df914e5895da511a8ae78712dc38deaf10915ee0a384d5fe' 
  AND token = 'ulM5VVrlyxEeMrdo7aUBHHSflGkYt3tZNshW1UugylU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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