SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dff8702b9df08399ce5eac14ed922c809dd11beb958a7aea01127e5299fe79df' 
  AND token = '1nlGRlGXWdEywOL+OzvD6ksTAfPUaGa79uJ/BQJ0Ico=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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