SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '328a598cca81683dbb68630a55fcfbfc116f58ece96b78cc658f2e766bee34c1' 
  AND token = 'l5gg8ZtF4eFCkxniTMGtwQScJBBsG/+7Mmp/+YXj9HI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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