SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4db009bcf15a9932de63aa295616171c91308a9ddec0ddfca05738b39a209f86' 
  AND token = 'ozNpvj4kgtuoI1zZZGzk0c8I68YiiBxeUrk4vgfK9uU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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