SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '859c5ed7694f7309f590485643f6686ba7e7657712743d63bbba37d34d551ce5' 
  AND token = 'qLax02T8IaRvA8iqKIkSkpzdnati2nBYTPijwChgZgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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