SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7f3cee23b875cbb04de9e1a99c4f3516e45ccc8d3b4e606fa46455688b8dd74' 
  AND token = 'PZjxeogMGqyQ/9S545/xJB96jFB1wK+iwgFfjThiaCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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