SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'da36cbe4d6812c19d089335ebd0664d7d9a0043288b9bcc094da08fd5e424231' 
  AND token = 'utxz3BBPO9/fArFFmaedrE+vCzmMoxBBsXb3JRYM/tA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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