SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b1754d6e282549d45dda806f3cb37ca57f7cf35a2d5eed3109eea76521cb4f6' 
  AND token = 'Do8JvovzqDbkFsBDh8mDSZfZ3MNp3PX9s+Z5NLJ/NuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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