SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24ebf44be565ebbe31d96e5120f9a6f13472d7e2a9e20f68da4d4666860ca203' 
  AND token = 'c+KWzume/6pV9BDjVWa5M2VmN0d/L5qDIDp3eHfyAaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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