SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8817f4b4ae1789cdbedcef198d2a76de832f16bbfcf2d69e331667ce2bdee3b4' 
  AND token = 'pUU+vQ6UvPDGrYlnH15Am6DjblndLimZ2B6+Jk2zB+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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