SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b06a556ad404e06a56eb47b6fdacac360e1177427e30aaaba7b18d40bf6dd46' 
  AND token = 'OG6VYkG9LSSE+VP7YOVexWMzGxuIissPHQ7P/EDl4NQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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