SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17d85b538c673577cdaddde70b06bafbb50381cfd66137834805dfba4353a4ab' 
  AND token = 'azecd3MgdWPbUXHWguet5D7/2AQRYxAj+W5AULAIafc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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