SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94ce0fdab8d2ef1b43d7ce47a2b57d1e98bbd5ae1db4834c605acb0f84fc808f' 
  AND token = '/z0LpMl7bCDuDp8tjJseCACCPlpmHdbjXr6UDeUW1dk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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