SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd7fa6fb8e5401a0adfc0edccba718acfd689a6a514ab891615de8529e87adf3' 
  AND token = 'P8Xnl6UmCZf6brnktYETsMbjpQ4JPkybld4ucmJ51Uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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