SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0eeb932eaa0f937b624f66574af7f17b585c555f3941bafb25340183942ff21' 
  AND token = 'MG4JHkEZz1LJOM6t6zelkzWm0ZhDGyrFrKTxJuqxabg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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