SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cc561708fe3c67bcd44d3f59d078a91f76630bff19b43ec9ef92ddd40249213' 
  AND token = 'nXn6hmGhRbjWZVUVq1QXVycZRMSLqBJTM4VpwgB8XMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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