SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3249213afda12e003cfc32c57c1206355cbf7f952aee692fbc05388f6905f3e7' 
  AND token = 'QvMsaOyqzHkRmYpqgTBGbVXeAhv+xHteXNz9NEcVxy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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