SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e1008c3daff2e77def01bcabd82767e76296a1986ca041ed4c744822f44be80' 
  AND token = 'DeN1PURxuEKLAWAc/Tbk9sdViJzQ05ShqGxlDigMMr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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