SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '694eafaba8724a4a570619aa1952d7c69f01151fc0ea64034131001fcdda3e57' 
  AND token = 'NLDqPmWbK0SWL0PKUEV5zRsHB5DHrOaLOSd68QkxzkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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