SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bc2eaa6817a6c7817382f4b9bce7cea4a5d80f166ed46cd24df5118f7af2b2c' 
  AND token = 'GwOxfs5l2kOG8huZcQKgME8BULwrB+/D9bnTcjTuFPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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