SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2378d690f89c91c518112358f1c5dd25c6a82d9d77ae7e60706b3a19ab73e5d1' 
  AND token = '9jxBHBstP0i/tZu+XPbow0qz/po+qoVkFjZ7o6YxZj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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