SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a41d4f16bfb8f8e0f491ff942337c7c92809bca5f9e873753d352c69f97da42' 
  AND token = 'pBIz3vQ2Akw/GKFZJxqGQN/VrMAIHWyMT+BWW6kHI5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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