SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36d25c2d47864052a932c3e9fb84fe350a4d1d6361b771f441018116f9a657fa' 
  AND token = 'ro8hMyaF01P2iVqXnwTHuTmrhZIMONOamclQ1P4WOoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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