SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7659f7c7796bd4f56ef6c5c27bc45206073a0b83412d7699570f8d2cce2da539' 
  AND token = '1ys8rz/mUHfodp/1TixNfhgLkxo+GGQ3lv1p8BqyJe4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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