SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '90d355e487ba1bf720fb0c379284d2a6390b5578d3595a9d6af786e1e21a63a3' 
  AND token = 'R8/PNyT+pRF0dMgUVFCoVXKhirmdnclUKlngIq4kxJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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