SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87541d83d7ffdc5d8c23e3a5f9686c3cb6e86d8213276aee403d13c17c26647b' 
  AND token = 'A2qAB1SWpGGg09SNDFCyv93wFx+uFCMJnQJRxU6hxlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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