SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ad82ae5796f2163eea3667583137804abd250f81ccbc7bfeff5abac483f0806' 
  AND token = '3QWnoFrb54QJIJYOEL5or1WtaDZKtyPjvf5qgt/y4u4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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