SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b524978a752a9f257bcf3c6720b788169143bd1702867dbb0d25f1683acf6255' 
  AND token = 'iWeBOO2Hc24S3cTh8iLJeKVwIjfbqJv+XVAhWLvKAk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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