SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81ffffe4674fb2e8efbac5bc683d9eaa260a2153c89bf0ca75a2a727f4a8522b' 
  AND token = '4v4BbzQqqu9dBjVCUW/b3KM1628+JAvhHvWYWSBwHOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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