SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cca2b7298c912adcf266bcfd7c86d19e936dd568cbd83da250029819835e18a9' 
  AND token = '3xwmWf5XP0+H+is1acfyD3eCIbWqn0JHQFZmXZkzWvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}