SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '699adfce9223bfdab95151c1dd847b947b33138fbd3c812971a38b3e1b2ff64f' 
  AND token = 'XjhICEtCwTrA8YDEDJVvYyCRaYlCMf1G9HM2H7fKQg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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