SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce7ead87a3e1876c82b5b770a1b08206f64df5b833f044b0d97cb9a47e25c6ac' 
  AND token = '4mmwUmt/8Zt2VQvHBEIqSY4YoLlMzI0MVPyHxwMFKvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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