SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c71215608917658c4ee2a6546c5905bbe22cda66f14475f206764f7e4dab9173' 
  AND token = 'I96/jXinIvok5i3aMQvKAbw6x0T5ccbMW10YtjW+SzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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