SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b0a92a46d091f6e015e93ffd0059f7e64581d822e4adee537ff0fa24971af33' 
  AND token = '389CAlBYbVSPpYVHxYn+XwsHLF2X1J9GDwUWVg74pyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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